Feeding mechanism for sewing machines



Jan. 19, 1932. Y c, THQBRQE ET AL 1,841,858

FEEDING MECHANISM FOR SEWING MACHINES Filed Oct. 5, 1927 2 Sheets-Sheet 1 W513i &1,

8 W 40 46 la 14) QWMU LL lbw JWJMWZV Jan. 19, 1932.

c. THOBROE ET AL 1,841,858

FEEDING MECHANISM FOR SEWING MACHINES Filed Oct. 3. 1927 2 Sheets-Sheet 2 1&2.

Patented Jan. 19, 1932 UNITED STATES esse Parent oi-"Fica CARL THOBBOE AND FRIEDRICH LU'IZ, OF STUT'IGAB'I', GERMANY, ASSIGNORS E9 UNIQN' SPECIAL MASOHINENFAIBBIK, G. I. 3. E, OF STUTTGART, GERMANY FEEDING MECHANISM FOR SEWING: MACHINES -Application filed October 3, 1927, Serial No. 283,876, and in. Germany November 15, 1926.

The invention relates to new and useful improvements in feeding mechanisms for sewing machines, and more particularly to an auxiliary feed which is associated with the main feed of the machine and which cooperates therewith in feeding the material.

An object of the invention is to provide a sewing machine having an ordinary feeding mechanism with auxiliary feeding devices which are located directly in rear of the feed dog and the presser foot, which auxiliary devices include cooperating rotating feeding rolls operating to pull the fabric and thus aid in the feeding of the material. A further object of the invention is to provide an auxiliary feeding device of the above type wherein the lower feeding roll is located beneath the work support and projects into an opening formed through the work support so as to cooperate with the roll above the work support in the gripping and pulling of the fabric through the machine.

A still further object of the invention is to provide a device of the above type wherein the lower feeding roll is intermittently operated in timing with the feed dog of the main feeding mechanism. I

A still further object of the invention is to provide a sewing machine of the above type wherein the main feeding mechanism includes a feed bar attached to and operated by a feed rocker, and wherein said feed bar is so constructed as to provide a space in which the lower feed roll may be located and operated.

These and other objects will in part be obvious and will in part be hereinafter more fully disclosed.

In the drawings which show by way of illustration one embodiment of the inventlOIlr Figure 1 is a view partly in end elevation and partly in vertical section showing'the sewing machine embodying the improvements;

Fig. 2 is a View partly in plan and partly in section showing the parts beneath the work support Fig. 3 is a plan view of the feed bar; Fig. 4; is a front view of the feed dog supporting bridge which serves to support the sections of the feed dog on the feed bar, and Fig. 5 is an end elevation of the supporting bridge shown in Fig. 4-. The sewing machine is provided with the usual frame 1, in which is mounted for reciprocation a needle bar 2. A presser bar 3 is also carried by the frame. Mounted on the base of the main frame of the machine is a work support 4, and a main actuating shaft 5 is located beneath the work support. The work support is provided with the usual throat plate having feed slots 4a therein. The fabric is fed across the work support by the main feeding mechanism having a fee dog 8, which, as shown in the drawings, includes three sections. The feed dog 8 is carried by a feed bar which is raised and lowered b an eccentric 6 mounted on the main sha 5. The feed bar is provided with the usual to bracket 7 which extends beneath the eccentric. The feed bar is moved back and forth by a feed rocker 9 which is likewise of the usual construction. This feed rocker 9 is oscillated by an eccentric strap 10 cooperating with an eccentric on the main shaft 5. An arm 11 attached to the feed rocker 9 is also attached to this eccentric strap. 10. The machine is provided with the usual needles, loopers and Spreaders. An eccentric strap 12 (see Fig. 2) cooperates with the eccentric on the main shaft 5, and this eccentric strap is connected to an arm 14 on a rock shaft mounted to oscillate about a vertical axis 13. The rock shaft is connected by a link 15 with so a shaft 17 which supports and operates the loopers. The rock shaft 14 is also connected through a thrust rod 16 to a shaft 1% which supports and operates the Spreaders. The stitch forming mechanism forms no part of no the present invention, and has only been referred to very briefly. The present invention is directed more particularly to an auxiliary feeding mechanism which cooperates with the main feeding no mechanism in the feeding of the fabric. In sewing heavy strips, such as awnings, tent fabric, automobile-covers, rubber bands under tension, and other similar materials, it is very desirable to employ an auxiliary device which m operates upon the materials in rear of the main feeding device for the purpose of gripping and pulling heavy fabrics through the machine. The present auxiliary device includes a pair of cooperating feeding rollers 20 and 21. These feeding rollers are located directly behind the presser foot, which is indicated at 19 in the drawings, and also directly in rear of the feeddog sections 8. The roller 20 is journaled in a yoke 22 carried by a bar 23 which is mounted to slide freely in the overhanging arm of the main frame 1 of the sewing machine. The presser bar 3 carries a collar 24 upon which the usual flat spring 25 bears. The spring tends to force the presser foot 19 yieldingly against the work support and the feed dog. The bar 23'carrying the roller 20 is provided with a collar 26 which is clamped thereto. This collar has a forwardly projecting arm on which a flat spring 27 rests, and this spring yieldingly forces the roller 20 in a downward direction and into contact with the roller 21. As a means for raising the main presser foot, a lever 28 is provided which is of the usual construction. The roller 20 is raised from the work support and the cooperating roller beneath the same by means of a lever 29 which is similar in construction to the lever 28.

The roller 21 is mounted on a shaft 50 which in turn is mounted in suitable bearings on the base of the main frame 1 of the machine. This shaft is given an intermittent rotation by an eccentric strap 31 cooperating with the eccentric on the main shaft 5. The eccentric strap carries a ball head 33. An arm 32 attached to a sleeve 34 mounted on the shaft 50 is connected to said ball head, so that as the main shaft rotates, the arm 32 will be oscillated. Mounted in the housing 35 from which the shaft 50 extends is a ratchet mechanism of the usual type. The sleeve 34 is a part of this ratchet mechanism. When the arm 32 is oscillated, through the ratchet mechanism, it will give the shaft 50 on which the roller 21 is mounted, a stepped movement in a forward direction. A suitable ratchet is, as usual, provided for preventing retrograde movement of the roller 21. Through this ratchet mechanism, the roller 21 is turned step by step, and in timing with the feeding movements of the main feed dog 8. The fabric being stitched passes beneath the presser foot, and then between the cooperating rollers of the auxiliary feed device. The work support 4 is provided with an opening 4", and the lower roller 21 extends up into this opening. The surface of the roller 21 is fluted. Likewise, the surface of the roller 20 is fluted, and these rollers intermesh with each other. As noted,

the lower roller is positively rotated intermittently, and through its rotation and the cooperating roller 20 which is turned thereby,

the fabric is pulled through the machine. The rollers turn in the direction indicated by the arrows in the drawings. The portions of the work support at the upper face thereof and adjacent the opening 4 are inclined downwardly toward the opening. This enables the point of gripping contact between the rollers to be slightly below the plane of the work support. The fabric will pass down into the recess and between the rollers.

The feed bar carrying the feed dog sections is designed particularly so as to provide a space for the operation of the roller 21. The roller 21 is located between the feed rocker and the main actuating shaft. The feed bar consists of two arms 41, 41, which are spaced from each other. The arms are provided with alined openings 38, 38 for the bar 39 at the top of the feed rocker. Thus it is that the feed bar is pivotally connected to the feed rocker. A cross bar 40 joins the arms 41, 41 at their rear ends. A cross bar 42 joins the feed bars 41, 41 at their front ends. This makes of the feed bar, a feeding frame, which is provided with a space 36 in which the feed roller 21 is located and operates. The sections of the feed dog are mounted on a support or bridge 43. This support or bridge is mounted in the recesses 45, 45 of the feed bars, and is secured therein by suitable screws 46. The lower end of the bridge members is slotted at 49 for these holding screws, and this permits of a limited vertical adjustment of the bridge or support for the sections of the feed dog. The bridge or support 43 projects backwardiy and overhangs the front end of the feed bars and the cross bar 42. The upper portion of the bridge 43 is substantially horizontal and is provided with a slot 48. The sections of the feed dog are mounted on this portion of the bridge, and are adjustabl secured thereto by bolts 47 passing throug 1 the slot 48. By loosening these bolts, the feed sections may be shifted transversely of the line of feed on the supporting bridge therefor.

From the above it will be apparent that a machine has been rovided wherein the auxiliary feeding mec anism is located directly in rear of the presser foot and of the feed dog, and is disposed very close to the presser foot. As a result, the pulling feed of the auxiliary feeding device will begin just as soon as the fabric has passed well beneath the presser foot. This has been accomplished without interfering in any way with the usual four motion feeding mechanism as the main feeding mechanism for the machine. Furthermore, inasmuch as the shaft on which the actuated roller of the auxiliary feeding mechanism is mounted is very close to the main actuating shaft, there is little or no unnecessary vibration in the parts. Then again, when the auxiliary feeding mechanism is disposed as described, the supporting bearings vides a support for the auxiliary feeding mechanism which cannot shift relative to the main parts of the machine, and therefore,

the timing of the parts can be readily maintained.

It is obvious that minor changes in the details of construction and arrangement of the parts may be made without departing from the spirit of the invention as set forth in the appended claims.

Having thus described the invention, what we claim as new and desire to secure by Letters-Patent, is

1. A sewing machine including in combination a work support, a main actuating shaft, a feed rocker at the rear of the work support, means actuated from said shaft for oscillating said feed rocker, a feed dog, a frame supporting said feed dog having spaced feed bars and connecting cross bars forming a space in the center of said frame, means for raising and lowering the feed dog from said actuating shaft, a shaft located between the feed rocker and the main actuating shaft, a feed roller mounted on said shaft, said work support having a recess directly above said roller into which said roller projects, said roller being disposed in the space formed in the frame supporting the feed dog, a cooperating feed roller located above the work support and directly above said lower feed roller, and means for intermittently actuating the feed rollers in timing with the feed dog.

2. A sewing machine including in combination, a supporting frame, a work support carried thereby, a main actuating shaft' mounted in bearings carried by said frame beneath the Work support, a feed rocker pivoted to said frame at the rear side of the work support, a roller shaft mounted in bearings carried by said frame intermediate the rocker and the main actuating shaft, a feeding mechanism including a main feed dog, means connected to the feed rocker for moving said feed dog back and forth, means for raising and lowering the feed dog, a feed roller directly in rear of the feed dog mounted on said roller shaft, means for intermittently rotating said roller shaft in timing with the movements of the feed dog, said work support having a recess therethrough in which said feed roller operates, and an upper feed roller above the work support cooperating with said feed roller beneath the work support.

3. A sewing machine including in combination, a supporting frame, a work support carried thereby, a main actuating shaft mounted in bearings carried by said frame beneath the work support, a feed rocker pivoted to said frame at the rear side of the work support, a roller shaft mounted in bearings carried by said frame intermediate the rocker and the main actuating shaft, a feeding mechanism including a main feed dog, means connected to the feed rocker for moving said feed dog back and forth, means for raising and lowering the feed dog, a feed roller directly in rear of the feed dog mounted on said roller shaft, means for intermittently rotating said roller shaft in timing with the movements of the feed dog, said work support having a recess therethrough in which said feed roller operates, an upper feed roller above the work support cooperating with said feed roller beneath the Work support, said means for moving the feed dog back and forth including a feed bar frame having spaced members one at each end of the lower feed roller said members being con-' nected to said feed rocker, cross bars connecting said spaced members, and a bridge member carried by said fee-d bar frame and supporting said feed dog.

4. A sewing machine including in combination a work support, a main actuating shaft, a feed rocker at the rear of the work support, means actuated by said shaft for oscillating said feed rocker, a feed dog, a feed bar connected to the feed rocker and supporting said feed dog, means for raising and lowering the feed dog, a shaft located between the feed rocker and the main actuating shaft, a feed roller mounted on said shaft, said work support having a recess directly above said roller, a cooperating feed roller located above the work support and directly above said lower roller, and means for intermittently actuating the feed rollers in timing with the feed dog.

In testimony whereof We affix our signatures.

CARL THOBROE. FRIEDRICH LUTZ. 

